
$a = 1;
# check the boolean condition using unless statement
unless( $a < 20 ){
    # if condition is false then print the following
    printf "a is not less than 20\n";
}
print "value of a is : $a\n";

$a = "123";
# check the boolean condition using unless statement
unless ( $a ){
    # if condition is false then print the following
    printf "a has a false value\n";
}
print "value of a is : $a\n";